The present invention relates to a battery pack for use as a drive power source for battery-powered apparatuses such as portable or laptop computer. More particularly, the invention relates to a battery pack which is equipped with a rechargeable secondary or storage battery such as Ni-Cd battery.
Recently, battery-powered electronic apparatuses using a rechargeable battery have been rapidly widely used. Especially, in the case of an electronic apparatus using a detachable battery pack equipped with a rechargeable secondary or storage battery, many users possess many battery packs in such a manner that when the electric power of a battery pack used with the electronic apparatus becomes weak due to consumption of power, the battery pack is then exchanged for another battery pack which has been fully recharged. Generally, the battery pack of this kind comprises a casing which is so constructed as to be detachably attached to the electronic apparatus body. A rechargeable storage battery having a positive and negative terminals is housed within the casing, and a pair of power electrodes connected to the positive and negative terminals of the storage battery, respectively, and disposed on an outer surface of the casing so as to be electrically connected to the apparatus body.
The above-mentioned battery pack has a disadvantage in that it is difficult for average users to confirm the remaining amount of electric power of the storage battery in the battery pack. Accordingly, accidents may occur when a battery pack which should have been fully recharged but not have been recharged in virtual due to short circuit caused by a user's mistake, trouble of a battery charger, the end of life of the battery etc., is connected to the electronic apparatus.